Energy storage system

ABSTRACT

An energy storage system includes a module housing and multiple battery cells with insulating material and discharge directing material positioned inside the module housing. Each of the battery cells has a first end and a second end. Further, each of the battery cells has a positive terminal and a negative terminal. The energy storage system includes a first interconnect and a second interconnect positioned over the battery cells. Multiple first cell connectors connect the positive terminals of the battery cells to the first interconnect. Multiple second cell connectors connect the negative terminals of the battery cells to the second interconnect. A top plate having an interior side and an exterior side is positioned over the first interconnect and the second interconnect. The top plate includes one or more weak areas with reduced integrity positioned above one or more battery cells.

CROSS REFERENCE TO RELATED APPLICATION

The present U.S. Utility patent application claims priority pursuant to35 U.S.C. § 121 as a divisional of U.S. Utility application Ser. No.15/411,154, entitled “ENERGY STORAGE SYSTEM”, filed Jan. 20, 2017, whichis hereby incorporated by reference in its entirety and made part of thepresent U.S. Utility patent application for all purposes.

TECHNICAL FIELD

The present disclosure relates to an energy storage system. Moreparticularly, the present disclosure relates to structural andelectrical aspects of the energy storage system.

BACKGROUND

Energy storage systems are used in a variety of contexts. For example,an electrical storage system can be used to store energy generated fromphotovoltaics. The energy storage systems of the present disclosureinclude “packs” of multiple cells stacked together. These cells andother components in a pack generate heat during operation, both duringthe charging process to store the energy and during the dischargeprocess when energy is consumed. When the cells fail, they typicallyrelease hot gases. These gases may impact the integrity of other cellsin the pack and may cause substantial damage to the functional cellswhich have not failed. Thus, an improved energy storage system isrequired which reduces or removes one or more of the issues mentioned.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1A illustrates a perspective view of a battery cell, according tocertain embodiments of the invention.

FIG. 1B illustrates a side view of a battery cell, according to certainembodiments of the invention.

FIG. 2 illustrates a perspective view of an array of battery cellspositioned inside a module housing, according to certain embodiments ofthe invention.

FIG. 3 illustrates a top view of the array of battery cells having aninterstitial material placed between the battery cells, according tocertain embodiments of the invention.

FIG. 4 illustrates a top view of the array of battery cells havingsleeves placed around the battery cells, according to certainembodiments of the invention.

FIG. 5 illustrates cooling tubes between battery cells to providecooling, according to certain embodiments of the invention.

FIG. 6 illustrates a first interconnect and a second interconnectpositioned over the battery cells, according to certain embodiments ofthe invention.

FIG. 7 illustrates an interconnect layer, according to certainembodiments of the invention.

FIG. 8 illustrates a detailed view of a portion of the interconnectlayer, according to certain embodiments of the invention.

FIG. 9A illustrates a top plate of the energy storage system havinghexagonal weak areas, according to certain embodiments of the invention.

FIG. 9B illustrates the top plate of the energy storage system havingcircular weak areas, according to certain embodiments of the invention.

FIG. 9C illustrates the top plate of the energy storage system havingpolygonal weak areas, according to certain embodiments of the invention.

FIG. 10 illustrates an exploded view of the energy storage system,according to certain embodiments of the invention.

FIG. 11 illustrates a side view of the energy storage system, accordingto certain embodiments of the invention.

FIG. 12 illustrates a method of assembling the energy storage system,according to certain embodiments of the invention.

FIG. 13A illustrates cooling elements within an energy storage systemaccording to certain embodiments of the invention.

FIG. 13B illustrates a cold plate within an energy storage systemaccording to certain embodiments of the invention.

Embodiments of the present disclosure and their advantages are bestunderstood by referring to the detailed description that follows. Itshould be appreciated that like reference numerals are used to identifylike elements illustrated in one or more of the figures, whereinshowings therein are for purposes of illustrating embodiments of thepresent disclosure and not for purposes of limiting the same.

DETAILED DESCRIPTION

The present disclosure relates to an energy storage system. Moreparticularly, the present disclosure relates to structural aspects ofthe energy storage system.

The energy storage system includes a module housing having multiplebattery cells positioned inside the module housing. Each of the batterycells has a first end and a second end. Further, each of the batterycells has a positive terminal and a negative terminal. A firstinterconnect is positioned over the multiple battery cells. A secondinterconnect is positioned over the multiple battery cells. Multiplefirst cell connectors connect the positive terminal of the battery cellsto the first interconnect. Similarly, multiple second cell connectorsconnect the negative terminal of the battery cells to the secondinterconnect. A top plate having an interior side and an exterior sideis positioned over the first interconnect and the second interconnect.The top plate includes one or more weak areas above the one or morebattery cell. The weak areas are regions that have less integrity andthus, where mechanical failure is more likely to occur if a battery cellreleases gas. These regions may be physically weaker areas compared tothe surrounding areas and may rupture when pressure builds up due to afailed cell. Alternatively, the weak areas may be chemically weaker andpreferentially rupture when exposed to the caustic gases released by afailed battery cell. The weak areas may also fail due to a combinationof physical and chemical weakening.

Aspects of the present inventions are described below in detail tospecific aspects or features with certain examples illustrated in theaccompanying drawings. Wherever possible, corresponding or similarreference numbers will be used throughout the drawings to refer to thesame or corresponding parts.

FIG. 1 illustrates a battery cell 100 in a perspective view through FIG.1A, and in a side view through FIG. 1B. With combined reference to FIGS.1A and 1B, the battery cell 100 may be any type of a conventionalbattery cell which may convert chemical energy of substances stored inthe battery cell 100 into electrical energy. The battery cell 100 has afirst end 102 and a second end 104. The battery cell 100 has a positiveterminal 106 and a negative terminal 108 towards the first end 102. Thepositive terminal 106 preferentially protrudes from the first end 102the battery cell 100 to allow a contact to be made to the positiveterminal 106 and differentiate the first end 102 from the second end104, although different geometries of the positive terminal 106 mayexist. The negative terminal 108 preferentially begins on the second end104 and continues on the outer surface 110 of the battery cell 100 andwraps at least to a portion of first end 102. The portion of the batterycell 100 that wraps from the outer surface to the first end may bereferred to the “shoulder” of the battery cell 100. The negativeterminal 108 preferentially is formed on the shoulder, so thatconnections to the negative terminal may be made on the shoulder. Inother words, the negative terminal 108 preferentially exists on shoulderof the battery cell 100. An insulation region 112 may be provided on thesurface 110 of the battery cell 100 such that the positive terminal 106and the negative terminal 108 do not short due to mutual contact. Theinsulating region 112 may be provide through any other means as well onarea of the surface 110 between the positive terminal 106 and thenegative terminal 108. In alternate embodiments, the positive andnegative terminals could be switched.

FIG. 2 illustrates an array of battery cells 100 positioned inside amodule housing 200. The module housing 200 may be a box shaped enclosurewhich may have means to accommodate the battery cells 100 in an uprightmanner as illustrated. According to certain embodiments of thisinvention, the module housing 200 includes a base 202 and four sidewalls 204 supported on the base 202. The side walls 204 may be attachedto the base 202 through any suitable mechanical joining means such asfasteners, adhesives etc. The module housing 200 may be an integral boxshaped structure as well. The base 202 of the module housing 200 mayinclude slots or any other such means (not shown) to accurately positionthe battery cells 100 inside the module housing 200. The modular housingmay include active cooling or electrical elements.

Battery cells 100 are preferentially positioned in a uniform directionwithin the module housing 200 such that the first end 102 of the batterycell 100 is facing towards top plate 900 as shown in FIG. 10 and thesecond ends 104 of the battery cells 100 are facing away from top plate900 and towards the base 202. The base may comprise a cold plate orsimply be a non-cooled plate. The base may be insulated so to preventthe formation of an electrical connection between battery cells 100through the base or other portions of the module housing. The batterycells 100 may be arranged in different orientations as dictated by thegeometrical and design constraints of the system. The battery cells 100may be arranged in rows and columns as illustrated or the battery cells100 may also be arranged in any other manner of stacking based on numberof the battery cells 100 being used as per application requirements.

During operation of the energy storage system, the battery cells 100generate heat. The system may include features or material to thermallyinsulate the battery cells 100 from the heat generated by other cells(and/or other electrical components), such as a polymer-based insulatingmaterial or another type of insulating material. The system may alsoinclude features, such as a cold plate or heat pipes, to remove heatgenerated by the battery cells 100 during operation of the energystorage system. The negative terminal of the battery cells 100 may existon the side of the cells. It may therefore be desirable to electricallyinsulate the battery cells 100 from each other. The energy storagesystem may include features or material to electrically insulate thebattery cells from each other and other electrical components for whichan electrical connection is not desired. The features or material toperform this electrical insulation may include the interstitial materialor a sleeve, as further described below. In alternate embodiments, anair gap may provide the necessary electrical isolation.

Further, the battery cells 100 may fail and discharge its contents ashot gases that are caustic to the other battery cells 100 and otherportions of the system. The energy storage system may include featuresor material for directing the hot-gas discharge during failure of abattery cell 100. In certain embodiments, the features or material forinsulating the battery cells from heat generated by other battery cells(and/or other electrical components) and the feature or material thatdirects the discharge of the hot gases during battery cell failure maybe the same. In other embodiments, separate features or materials mayboth insulate a battery cell from the other battery cells and alsodirect the discharge of any hot gases. The insulation material orfeature may be interstitial material 300 (shown in FIG. 3) or sleeve 400(shown in FIG. 4). Similarly, the feature or material for directing thedischarge of hot gases may be interstitial material 300 or a sleeve 400.

FIG. 3 illustrates a top-down view of the array of battery cells 100with the interstitial material 300 between the battery cells 100. Theinterstitial material 300 may thermally insulate the battery cells 100from the heat generated by other battery cells 100 and may alsoelectrically insulate the battery cells 100 from each other, which maybe necessary as the negative terminal may exist on side of a batterycell. The interstitial material 300 may also direct any dischargegenerated from failure of the battery cells 100 away from the otherbattery cells 100.

Separate materials may also be used to thermally and/or electricallyinsulate the battery cells 100 and directing the discharge generatedfrom failure of the battery cells 100 away from the array of the batterycells 100. For example, this could occur by providing a firstinterstitial material around the cells that is thermally and/orelectrically isolating. If this material is insufficient to fully directany hot-gas discharge from a failed cell, for example, due to theporosity of the material, then a second interstitial material may bedisposed around the first interstitial material to cause the desireddischarge direction.

The interstitial material 300 may be selected from a variety ofmaterials including, but not limited to, thermally insulating materialsin the form of foams, fabrics, battings, intumescent materials, andrelated insulation materials known in the art of thermal insulation.This includes polymeric foams such as silicones, epoxies, urethanes,polyimides, aromatic polyethers and sulfones, and phenolicfoams—materials generally known as having high thermal stability. Itadditionally includes syntactic foams (resin-based materials with hollowmircobubble filler) formed from the same classes of polymers. This canbe extended to include bound assemblies of insulating particles (likemicrobubbles) bound together with a binder rather than fully immersed ina resin matrix. It also includes non-polymeric foams such as aerogelsand porous ceramics. Fabrics and battings include ceramic and glassfiber felts, papers, fabrics, and battings. Intumescent materials, whichare materials that expand and char in the presence of heat, can beincorporated either as a free-standing fill material, or incorporatedinto the above options of foams, syntactic foams, or fabric-likematerials. As such, the fill material can be a combination of abovementioned classes of materials. The fill material can be furtherenhanced by the incorporation of flame suppressant and fire retardantmaterials known in the art fire-resistance.

The interstitial material 300 may be disposed in spaces between thebattery cells 100 in the module housing 200 by adding the materialthrough ports in one or more side walls 204 of modular housing.Alternatively, the material may be added from the top, after batterycells have been placed into position within the modular housing,excluding the top plate. Additional approaches of incorporating the fillmaterial include placing preformed inserts of thermal insulation intothe interstitial gaps during assembly, or after cell assembly but beforethe final enclosure is closed. When a multiple types of interstitialmaterials are used, other techniques may be used. For instance, thefirst interstitial material may be coated through, for example, dipcoating or spin coating, followed by the addition of the second materialthrough a coating technique or adding the interstitial material througha port in the side wall or from the top, after the battery cells havebeen placed into position within the modular housing, excluding the topplate.

FIG. 4 illustrates a top-down view of another embodiment of the presentinvention with sleeves around the battery cells. Sleeves 400 arepreferentially provided around one or more battery cells 100. In certainembodiments, sleeves may be provided around every battery cell 100. Inalternate embodiments, sleeves may be provided around less than everybattery cell 100, but such that each battery cells is electricallyand/or thermally isolated from one another.

Sleeves 400 may serve similar function as the interstitial material 300,specifically to electrically isolate battery cells 100 from each other(and other electrical components), thermally isolate battery cells 100from each other (and other thermal components), and/or direct thedischarge of any hot gases that result from the failure of a batterycell. Sleeve 400 may be a cylindrical sleeve having an inside surfaceconforming to an outer surface of the battery cell 100. The sleeve 400may have an inner diameter the same, or even slightly smaller, than anouter diameter of the battery cells 100 so that the sleeve 400 may bepress fit on the battery cell 100. The sleeve 400 may be attached to thebattery cells 100 in any other suitable manner as well. The sleeve 400may include gaps or spaces to allow electrical connection to thepositive terminal 106 and the negative terminal 108 of the battery cell100, for example, if the connection to the negative terminal is made tothe side of a battery cell and not to the shoulder of the battery cell.Using sleeve 400 may allow for higher packing efficiency and reduce theamount of material necessary to provide the desired properties, such aselectrical or thermal insulation, or directing hot-gas discharge in acertain direction.

In certain embodiments, sleeve 400 and interstitial material 300 mayoccur together. For instance, a sleeve 400 may be disposed around one ormore battery cells (for example all of the battery cells, or less thanall but sufficient to provide the necessary function), to providethermal insulation, electrical insulation, and/or direct the dischargeof failed cells. If the sleeve does not provide all the desiredproperties, interstitial material 300 may be disposed in spaces betweenthe battery cells 100 with sleeves (keeping in mind that not all batterycells need to have sleeves) by adding the interstitial material throughports in one or more side walls 204 of modular housing. Alternatively,the interstitial material may be added from the top, after battery cellshave been placed into position within the modular housing, excluding thetop plate.

FIG. 5 illustrates a cooling tube used to remove heat generated bybattery cells according to certain embodiments. As shown in FIG. 5,cooling tubes 500 are arranged between rows of the battery cells 100. Inother embodiments, multiple cooling tubes 500 may be provided betweenthe battery cells 100. Any suitable arrangement of the cooling tubes 500may be provided between the battery cells 100 as cooling demandsrequire. The cooling tubes 500 remove heat from the battery cells 100and help keep the temperature within acceptable limits. In certainembodiments, interstitial material 300, sleeves 400, and the coolingtubes 500 are used in combination within one another. For example, thecooling tubes 500 may be provided inside the module housing 200 to helpcool the battery cells 100 and then the interstitial material 300 may beprovided around the battery cells 100 and the cooling tubes 500 to helpdirect any discharge from a failed battery cell 100. Cooling tubes 500preferentially have internal lumens (i.e., internal divided walls) thatimprove heat transfer. U.S. patent application Ser. No. 14/056,552describes features of cooling tubes for thermal management as can beused within an energy storage system of the present invention. Theentire disclosure of U.S. patent application Ser. No. 14/056,552 isincorporated herein by reference.

In other embodiments, instead of cooling tubes, heat pipes are disposedbetween the battery cells to remove generated heat. Heat pipes may bemade by extruding tubes or other shapes of metal or another materialthat has a high thermal conductivity. During the extrusion process,small fins that function as capillaries are created. The extruded tubeor other shape is filled with liquid, air is evacuated, and then thetube or other shape is sealed such that a liquid/gas mixture existswithin the sealed tube or shape. Heat pipes provide cooling through theevaporative process in which liquid in thermal contact with hotterregions absorbs heat and may undergo a phase transformation from liquidto gas. The gas reaches a region cold enough to remove enough heat formthe gas, the gas then condenses back to a liquid. The liquid may migrateback to the heat source with the help of capillary action from the finsformed during the extrusion process. U.S. patent application Ser. No.14/189,219 describes additional features of heat pipes for thermalmanagement within an energy storage system, the disclosure of which isincorporated herein by reference.

In certain embodiments, a cold plate (which provides liquid cooling) maybe in thermal connection with the battery cells 100 to further removeheat generated during system use. The cold plate may be in directthermal contact with the battery cells 100 or, alternatively, one ormore layers and/or features may be between the cold plate and thebattery cells 100. In certain embodiments, the battery cells 100 are incontact with one or more heat pipes to remove excess heat disposed underthe battery cells. A cold plate is disposed below the heat pipe or pipes(on the side of the heat pipe away from the battery cells 100) thathelps dissipate the heat contained in the heat pipe.

In certain embodiments, the cold plate may be in thermal contact withone side of the cells without any heat pipes disposed between the cells.The cold plate may physically consist of a single plate or multipleplates that are thermally connected to the cells and/or one another. Inother embodiments, one or more heat pipes are disposed between thebattery cells 100 and a cold plate is disposed below the battery cells100. The heat pipes and the cold plate may be in thermal connection withone another.

Additional details of embodiments that incorporate heat pipes and coldplates are described with reference to FIGS. 13A and B. FIGS. 13A and13B illustrate one or more cooling elements with an energy storagesystem according to certain embodiments. FIG. 13A illustrates an energystorage system with a heat pipe 1300 and cold plate 1302. In theembodiments illustrated in FIG. 13A, heat generated by the battery cells100 is removed using both heat pipe 1300 and a cold plate 1302. Adhesivelayer 1304 bonds heat pipe 1300 and cold plate 1302. As shown in FIG.13A, heat pipe 1300 is coated with a dielectric coating layer on eachside, and cold plate 1302 is coated with a dielectric coating layer onthe side closest to cold plate 1302. When the heat pipe 1300 and coldplate 1302 are coated with dielectric coating layers as shown in FIG.13A, adhesive layer 1304 bonds directly to dielectric coating layers1306 and 1310. Similarly, adhesive layer 1312 bonds the battery cells toheat pipe 1300. As shown in FIG. 13A, adhesive layer bonds 1312 bondsdirectly battery cells 100 and to dielectric coating layer 1308 on heatpipe 1300. Adhesive layers 1304 and 1312 preferentially comprise anadhesive with a high thermal conductivity that are dielectrics, althoughthe adhesive layer may comprise any type of adhesive that provides thenecessary adhesive force between the elements to be bonded (for example,between heat pipe 1300 and the cold plate 1302). Cold plate 1302, whichis thermally coupled to the heat pipe 1300, removes heat from the heatpipe as shown in FIG. 13A and directly from battery cells as shown inFIG. 13B.

In certain embodiments, one or more of the dielectric coating layers maybe omitted. When a dielectric coating layer is not present, adhesivelayer 1304 or adhesive layer 1312 may bond directly to either the heatpipe or cold plate. For example, if dielectric coating layer 1306 is notpresent, then adhesive layer 1304 would bond directly to cold plate 1302but to heat pipe 1300 through dielectric coating layer 1310. Inalternate embodiments, additional layers may be present between the heatpipe and cold plate or the heat pipe. Additional layers may also bepresent between the heat pipe and battery cells. In other embodiments,one or more of the adhesive layers 1304 and 1312 may be omitted.

FIG. 13B illustrates an embodiment with the cold plate thermallyconnected to battery cells without a heat pipe. As shown in FIG. 13B,cold plate 1302 is coated with dielectric coating layer 1306. Thebattery cells 100 are bonded to the cold plate through the dielectriccoating layer 1306 using adhesive 1312. As described above, thedielectric coating layer may be omitted, in which case the battery cellsare directly bonded to the cold plate using adhesive. Also, in certainembodiments, additional layers are present.

FIG. 6 illustrates a first interconnect 602 and a second interconnect600 positioned over the battery cells 100. Although, the battery cells100 are shown along with the sleeve 400, it should be understood thatthe battery cells 100 may also be provided without the sleeves 400. Thefirst and second interconnects 602 and 600 may be plates of metal.Further, an underside of the first and second interconnects 602, 600(that is the side closer to the battery cells 100) is preferablyelectrically insulated so as to not form unintended electricalconnections through the contact of the first and second interconnects602, 600 with a cell terminal. As shown in FIG. 6, the electricalconnections are made using first and second cell connectors 604, 606.

The first and second interconnects 602 and 600 are used to charge anddischarge the battery cells 100 during operation of the energy storagesystem. The first interconnect 602 (or set of interconnects) isconnected to the positive terminals 106 the battery cells 100 and thesecond interconnect 600 (or set of interconnects) is connected to thenegative terminals 108 of the battery cells 100. The first cellconnector 604 connects the positive terminal 106 of each battery cell100 to the first interconnect 602. The first cell connector 604 may be awire or another electrical connection and is connected to the positiveterminal 106 of the battery cell 100. The second cell connector 606,which may also be a wire or other electrical connection, connects thenegative terminals 108 of the battery cells 100 to the secondinterconnect 600. The second cell connector 606 may be connected to anyportion of the negative terminal 108 of the battery cell 100. Thenegative terminal 108 of the battery cell 100 may run from the end awayfrom the positive terminal 106, up the side of the battery cell 100, andeven around to the side of the positive terminal 106, that is on the“shoulder” of the first end 102. The negative terminal may even bedisposed significantly on the first end 102, provided that the positiveand negative terminals are electrically isolated from one another. Thesecond cell connector 606 may contact the negative terminal of thebattery cell 100 on the shoulder of the battery cell 100. In alternateembodiments, the positive and negative terminals could be switched.

As shown in FIG. 6, the positive terminals 106 of the battery cells 100are connected to the first interconnect 602 through the multiple firstcell connectors 604 and all the negative terminals 108 of the batterycells 100 are connected to the second interconnect 600 through themultiple second cell connectors 606. That is, all of the battery cells100 shown in FIG. 6 are electrically connected in parallel. A group ofthe battery cells 100 that are electrically connected in parallel may beelectrically connected to another group of the battery cells 100 inseries.

The first and second interconnects 602 and 600 lie in same horizontalplane above the battery cells 100. The first cell connector 604 and thesecond cell connector 606 may protrude slightly above the first andsecond interconnects 602 and 600. The first and second interconnects 602and 600 may also include grooves etc. to accommodate the first andsecond cell connectors 604, 606 in the same horizontal plane in whichthe first and second interconnects 602 and 600 lie. In certainembodiments, the top plate 900 (shown in FIG. 9) comprises a featurethat allows the first and second cell connectors 604, 606 to protrudeupward from the battery cell 100. For example, the top plate 900 mayhave material removed such that the first and second interconnects 602and 600 may protrude uninhibited. In other embodiments that include oneor more sleeves 400, the sleeves 400 may include gaps or spaces to allowthe first and second interconnects 602 and 600 to be connected to thepositive and negative terminals 106, 108 respectively without inhibitingthe top plate 900 from being placed over the battery cells 100.

FIG. 7 illustrates another embodiment of the present disclosure in whichthe first and the second cell connectors 604 and 606 are formed in thesame plane as the first and second interconnects 602 and 600. Thisphysical interconnect layer 700 includes a connection means for both thepositive terminal 106 and the negative terminal 108 of the battery cells100. The connection means may be a portion of a metal sheet, the metalsheet including cell connectors and an interconnect (or set ofinterconnects). Like in the embodiments described with reference to FIG.6, the interconnects may contain an electrical insulation layer toprevent unintended electrical connections. Electrical insulation mayeither be removed, or not present, in the regions where an electricalconnection to the positive terminal 106 or the negative terminal 108 ismade. Blocks of the battery cells 100 may be connected in parallel withone another and also connected in series.

FIG. 8 illustrates further structural details of the interconnect layer700. The interconnect layer 700 may connect both the positive terminal106 and the negative terminal 108 of the battery cells 100. Theinterconnect layer includes a positive interconnect 802 and a negativeinterconnect 804. The positive interconnect 802 connects the positiveterminals 106 of the battery cells 100 with the interconnect layer 700and the negative interconnect 804 connects the negative terminals 108 ofthe battery cells 100 with the interconnect layer 700.

The positive interconnect 802 connects the positive terminals 106 of thebattery cells 100 at multiple first connection points 806. Similarly,the negative interconnect 802 connects the negative terminal 108 of thebattery cells 100 at multiple second connection points 808. The firstconnection point 806 and the second connection point 808 may beintegrated portions of the positive interconnect 802 and the negativeinterconnect 804 respectively. The first connection points 806 and thesecond connection points 808 typically lie in same horizontal plane asof the positive and negative interconnects and may be formed from thesame material as the interconnects. The positive interconnects 802 andthe negative interconnects 804 may also be formed from the samematerial.

For example, as shown in FIG. 8, current may flow from left to right.The battery cells 100 on the left side may be electrically connected inparallel with one another and then connected in series with the batterycells 100 to the right. As shown in FIG. 8, blocks of the battery cells100 are defined through dashed lines 880, 890. The battery cells 100shown within the dashed lines 880 are electrically connected in parallelwith each other. This group of the battery cells 100 is then connectedin series with the group of the battery cells 100 shown within thedashed lines 890. The group of the battery cells 100 within the dashedlines 890 is connected in parallel with each other. This description isexplanatory only; other configurations of with different number ofbattery cells 100 in series and parallel are possible as well.

The top plate 900 is placed over the first and second interconnects 602and 600. FIG. 9A-9C illustrate structural details of the top plate 900.The top plate 900 includes multiple weak areas 904. In certainembodiments, the interior side 902 contains the multiple weak areas 904positioned above the battery cells 100. In other embodiments, the weakareas 904 may be on the exterior portion of the top plate. The number ofthe weak areas 904 on the interior side 902 of the top plate 900 mayvary as per the application requirements. The weak areas 904 arestructurally weaker portions of the top plate 900. The weak areas 904may have any suitable geometry as per the need of the present invention,including a hexagonal geometry, a circular geometry, or an irregulargeometry to accommodate other features or elements of the energy storagesystem.

For example, as shown in FIG. 9A, the weak areas 904 have a hexagonalgeometry. As shown in FIG. 9B, the weak areas 904 have a circulargeometry with portion of material removed along the circumference. Theportion of material removed may be notches provided along thecircumference. In other embodiments, the weak areas 904 may have anirregular polygon geometry, such as the geometry shown in FIG. 9C toaccommodate the first and second cell connectors 604 and 606 to thepositive terminal 106 and the negative terminal 108.

The weak areas may be used to direct hot gases when a battery cell failsand expels its contents. The weak areas help direct the hot gases todesirable discharge locations, and more importantly away from lessdesirable areas such as the other battery cells. The hot gases aretypically caustic and may cause other battery cells to fail ifsufficient amounts of the caustic gasses are exposed to the other cells.Creating weak areas helps direct the caustic gases away from the otherbattery cells 100 and minimize damage from the failure of a batterycell.

The top plate 900 is designed to allow the gases from a failed batterycell to be expelled once the weak area 904 above the failed cellruptures. The weak area preferentially ruptures because of the increasedpressure from the gases and/or the caustic gases impinging on the weakerareas causing rupture. Once rupture occurs, the gases may be expelledexternal to the modular housing.

Top plate 900 with weak areas 904 may be manufactured in different ways.For example, the top plate 900 may be prepared from a single material. Aportion of material may be removed from the top plate 900 at theintended position of the weak areas 904 such that a thickness of the topplate 900 is lesser at the weak areas 904 as compared to a thickness ofthe top plate 900 at other locations. Therefore, the weak areas 904 maybe groves or structural depressions on the interior side 902 of topplate 900. Alternatively, the weak areas 904 may be grooves orstructural depressions on the exterior side of top plate 900.

In another embodiment, top plate 900 may comprise a thick or structurallayer and has an opening above each battery cell. The openings may beany shape that would allow for gas to be expelled when a battery cellfails and may be shaped to provide space for other components, such asprotruding interconnects or cell connectors. A thin layer, such as athin layer of mica, may then be bonded (or otherwise added) to the thickor structural layer. The thin layer covers the openings in the thick orstructural layer. This thin layer should be thin enough to rupture whenthe pressure builds up from a failed battery cell. The thin layerpreferentially only ruptures over the failed battery cell, leaving theremaining cells (that have not failed) covered. The thick or structurallayer, may be bonded to the thin layer through various means including asuitable adhesive, by bonding the layers with the aid of heat, or anyother means suitable for the materials that comprise the material of topplate 900.

In other embodiments, the weak areas 904 are formed on the top plate 900by manufacturing the top plate 900 by a composite material. For example,the top plate 900 may be manufactured by a mica layer having a steelmesh on top. The steel mesh may afterwards be removed from the portionsof the top plate 900 which are intended to be the weak areas 904,leaving only mica above the battery cells 100. Thus, the weak areas 904are rendered structurally weaker and in case of application of a forcesuch as by the hot gases coming out of the failed battery cells 100, thetop plate 900 fails at the weak areas 904. The methods of manufacture,and compositions of, the top plate 900 described herein are merelyexemplary in nature and any variations in the material as well asmanufacturing processes may be made as per application requirements. Topplate 900 may comprise other materials including metal (with addedelectrical insulation to prevent any unwanted electrical), ceramic,metal with mica, fire retardant composites, plastics, or any othermaterial that can provide the necessary structural insulatingproperties.

FIG. 10 illustrates an expanded view of an energy storage system 1000showing various components. The module housing 200 typically includesthe base 202 and the four side walls 204, but one or more elements, suchas a side wall 204, may be removed. The module housing 200 is generallyelectrically isolated from the housed battery cells 100. This may occurthrough physical separation or through an electrically insulating layer.In certain embodiments, the base 202 comprises an electricallyinsulating layer on top of a metal sheet. In other embodiments, the base202 is formed from a nonconductive or electrically insulating material,such as polypropylene, polyurethane, polyvinyl chlorine, anotherplastic, a nonconductive composite, or an insulated carbon fiber. Sidewalls 204 may also contain an insulating layer or be formed out of anonconductive or electrically insulating material, such aspolypropylene, polyurethane, polyvinyl chlorine, another plastic, anonconductive composite, or an insulated carbon fiber.

According to specific embodiments of this invention, the side walls 204include protrusions 1002 which may fit in holes 1004 provided in thebase 202 to couple the side walls 204 to the base 202. The battery cells100 are placed on the base 202 in a pre-determined positionalarrangement as per the application requirements for which the energystorage system 1000 is to be used. The interconnect layer 700 includingthe first interconnect 602 and the second interconnect 600 is positionedabove the battery cells 100. The top plate 900 is positioned over theinterconnect layer 700. The top plate 900 may either be a single plateor the top plate 900 may include multiple top plates 900 as illustrated.The multiple top plates 900 may be coupled with each other in anysuitable manner as per the scope of the present invention. The top plate900 includes an exterior side 1006 which is planar as opposed to theinterior side 902 having structural depressions.

FIG. 11 illustrates a side view of the energy storage system 1000.Dimensions of the module housing 200, the interconnect layer 700 and thetop plate 900 are such that the battery cells 100 are efficientlypackaged inside the module housing 200 and the interconnect layer 700 isin contact with the positive terminals 106 and negative terminals 108 ofthe battery cells 100. The interconnect layer 700 and the top plate 900have similar dimensions. The module housing 200 has length and widthdimensions matching the corresponding dimensions of the interconnectlayer 700 and the top plate 900. The base 202 and the side walls 204 ofthe module housing 200 accordingly have appropriate dimensions.

FIG. 12 illustrates a method 1200 to create an energy storage system1000 according to certain embodiments. The energy storage system 1000includes the module housing 200. According to method 1200, at step 1202battery cells 100 are positioned inside the module housing 200. Thebattery cells 100 have the first end 102 and the second end 104. Eachbattery cell 100 include a positive terminal 106 and a negative terminal108. The battery cells 100 may be positioned at a pre-determinedposition defined by the slots or any other such means on the base 202 ofthe module housing 200 or alternatively though a computer-assistedmechanism, as would be known to those or skill in the art, to use adatum on the module housing to properly locate the cells. At step 1204,the positive terminals 106 of the battery cells 100 are coupled to thefirst interconnect 602 through the multiple first cell connectors 604.The first cell connectors 604 may be any suitable electrical joiningmeans such as wires. At step 1206, the negative terminal 108 of thebattery cells 100 are coupled to the second interconnect 600 through themultiple second cell connectors 606. The second cell connectors 606 maybe any suitable electrical joining means such as wire.

Alternatively, the connections to the positive and negative terminalsmay be coupled to the interconnect layer 700 through first interconnects602 and second interconnects 600 that all lie in the same horizontalplane. At step 1208, the top plate 900 is positioned over the firstinterconnect 602 and the second interconnect 600. The top plate 900includes the one or more weak areas 904 above the one or more batterycells 100. The weak areas 904 are structurally weaker portions of thetop plate 900.

The top plate 900 may be manufactured according to different techniquesand from different materials to produce the weak areas 904. For example,the top plate 900 may be formed from a single material. A portion ofmaterial may be removed from the top plate 900 at the intended positionof the weak areas 904 such that a thickness of the top plate 900 islesser at the weak areas 904 as compared to a thickness of the top plate900 at other locations. Thus, the weak areas 904 may be groves orstructural depressions on the interior side 902 of the top plate 900.The weak areas 904 may be groves or structural depressions on theexterior side of the top plate 900. Other ways as described herein andas would be known to persons of skill in the art to form weak areas maybe used.

Method 1200 may further include positioning the interstitial material300 between the battery cells 100. Interstitial material 300 can provideelectrical insulation and/or thermal insulation to the battery cells100. The interstitial material can also direct cell discharge from afailed battery cell. Method 1200 may also include positioning a sleeve400 around one or more battery cells 100. The sleeve may be used eitherin place of or in conjunction with any interstitial material. Method1200 may also include positioning cooling tubes 500 between the batterycells 100 to provide cooling to the battery cells. Further, method 1200may include positioning one or more cold plates in thermal connectionwith the battery cells to dissipate heat. The one or more cold platesmay be positioned on the base 202 of module housing 200, oralternatively instead of the base 202. When the cold plate is placed ontop of the base 202, or instead or base 202, the battery cells arepositioned on top of the cold plate instead of base 202 at step 1202.Alternatively, battery cells could be thermally connected to one or moreheatsinks. Heat may then be removed by circulating ambient or chilledair around the heat sink.

The method 1200 may include positioning any combination of theinterstitial material, sleeves, heat pipes, and/or cooling tubes. Theinterstitial material 300 may be added after the battery cells 100 arewithin the module housing 200. For example, the interstitial material300 may be added through ports in the side wall 204. The interstitialmaterial 300 may also be added from the top prior to assembly of thefirst and second interconnects 602, 600 and the top plate 900.

The foregoing disclosure is not intended to limit the present disclosureto the precise forms or particular fields of use disclosed. As such, itis contemplated that various alternate embodiments and/or modificationsto the present disclosure, whether explicitly described or impliedherein, are possible in light of the disclosure. Having thus describedembodiments of the present disclosure, a person of ordinary skill in theart will recognize that changes may be made in form and detail withoutdeparting from the scope of the present disclosure. Thus, the presentdisclosure is limited only by the claims.

In the foregoing specification, the disclosure has been described withreference to specific embodiments. However, as one skilled in the artwill appreciate, various embodiments disclosed herein can be modified orotherwise implemented in various other ways without departing from thespirit and scope of the disclosure. Accordingly, this description is tobe considered as illustrative and is for the purpose of teaching thoseskilled in the art the manner of making and using various embodiments ofthe disclosed air vent assembly. It is to be understood that the formsof disclosure herein shown and described are to be taken asrepresentative embodiments. Equivalent elements, materials, processes orsteps may be substituted for those representatively illustrated anddescribed herein. Moreover, certain features of the disclosure may beutilized independently of the use of other features, all as would beapparent to one skilled in the art after having the benefit of thisdescription of the disclosure. Expressions such as “including”,“comprising”, “incorporating”, “consisting of”, “have”, “is” used todescribe and claim the present disclosure are intended to be construedin a non-exclusive manner, namely allowing for items, components orelements not explicitly described also to be present. Reference to thesingular is also to be construed to relate to the plural.

Further, various embodiments disclosed herein are to be taken in theillustrative and explanatory sense, and should in no way be construed aslimiting of the present disclosure. All joinder references (e.g.,attached, affixed, coupled, connected, and the like) are only used toaid the reader's understanding of the present disclosure, and may notcreate limitations, particularly as to the position, orientation, or useof the systems and/or methods disclosed herein. Therefore, joinderreferences, if any, are to be construed broadly. Moreover, such joinderreferences do not necessarily infer that two elements are directlyconnected to each other.

Additionally, all numerical terms, such as, but not limited to, “first”,“second”, “third”, “primary”, “secondary”, “main” or any other ordinaryand/or numerical terms, should also be taken only as identifiers, toassist the reader's understanding of the various elements, embodiments,variations and/or modifications of the present disclosure, and may notcreate any limitations, particularly as to the order, or preference, ofany element, embodiment, variation and/or modification relative to, orover, another element, embodiment, variation and/or modification.

It will also be appreciated that one or more of the elements depicted inthe drawings/figures can also be implemented in a more separated orintegrated manner, or even removed or rendered as inoperable in certaincases, as is useful in accordance with a particular application.

LIST OF ELEMENTS

-   100 Battery cell-   102 First end-   104 Second end-   106 Positive terminal-   108 Negative terminal-   110 Surface-   112 Insulating region-   200 Module housing-   202 Base-   204 Side wall-   300 Interstitial material-   400 Sleeve-   500 Heat pipe-   600 Second interconnect-   602 First interconnect-   604 First cell connector-   606 Second cell connector-   700 Interconnect layer-   802 Positive interconnect-   804 Negative interconnect-   806 First connection point-   808 Second connection point-   880 Dashed line-   890 Dashed line-   900 Top plate-   902 Interior side of the top plate-   904 Weak areas-   1000 Energy storage system-   1002 Protrusion-   1004 Hole-   1006 Exterior side of the top plate-   1200 Method-   1202 Step-   1204 Step-   1206 Step-   1208 Step-   1300 Heat pipe-   1302 Cold plate-   1304 Adhesive layer-   1306 Coating layer-   1308 Coating layer-   1310 Coating layer-   1312 Adhesive

What is claimed is:
 1. A method of assembling an energy storage system,the method comprising: positioning a plurality of battery cells inside amodule housing, wherein each of the plurality of battery cells includesa first end and a second end, each of the plurality of battery cellsfurther includes a positive terminal and a negative terminal; couplingthe positive terminal of the plurality of battery cells to a firstinterconnect through a plurality of first cell connectors; coupling thenegative terminal of the plurality of battery cells to a secondinterconnect through a plurality of second cell connectors; andpositioning a top plate over the first interconnect and the secondinterconnect, wherein the top plate includes one or more weak areaspositioned above the first end or the second end of one or more batterycells of the plurality of battery cells, wherein the top plate comprisesmaterial that has been modified to reduce integrity of the top plate inthe one or more weak areas.
 2. The method of claim 1 further comprisingadding interstitial material between the plurality of battery cells. 3.The method of claim 1 further comprising adding a sleeve around one ormore of the plurality of battery cells.
 4. The method of claim 1 furthercomprising adding one or more heat pipes between or under the pluralityof battery cells.
 5. The method of claim 1, wherein the energy storagesystem further comprises an interconnect layer, the interconnect layerincluding the first interconnect and the second interconnect.
 6. Themethod of claim 1, wherein the weak areas in the top plate arephysically weaker portions of the top plate.
 7. The method of claim 1,wherein the weak areas are structural depressions in the top plate. 8.An energy storage system comprising: a module housing; a plurality ofbattery cells positioned inside the module housing, each of theplurality of battery cells including a first end and a second end, eachof the plurality of battery cells further including a positive terminaland a negative terminal; material for insulating the plurality ofbattery cells; material for directing a discharge from a failure of oneor more battery cells; a plurality of first cell connectors coupled tothe positive terminal of the battery cells; a plurality of second cellconnectors coupled to the negative terminal of the battery cells; aninterconnect layer positioned over the plurality of battery cells, theinterconnect layer including: a first interconnect configured to couplethe plurality of first cell connectors to the first interconnect; and asecond interconnect configured to couple the plurality of second cellconnectors to the second interconnect; wherein the first interconnectand the second interconnect lie in a same horizontal plane above theplurality of battery cells; and a top plate positioned over theinterconnect layer, wherein the top plate includes one or more weakerportions above the first end or the second end of one or more batterycells of the plurality of battery cells, wherein the top plate comprisesmaterial that has been modified to reduce integrity of the top plate inthe one or more weak areas.
 9. The energy storage system of claim 8,wherein the material for insulating the battery cells and the materialfor directing the discharge from the failure of one or more batterycells are the same material.
 10. The method of claim 1, wherein the weakareas are chemically weaker portions of the top plate.
 11. The method ofclaim 1, wherein the weak areas physically weaker and chemically weakerportions of the top plate.
 12. The method of claim 1, wherein a firstthickness associated with at least one weak area is less than a secondthickness associated with the top plate.
 13. The method of claim 1,wherein the top plate is a composite material comprising a mica layerwith a steel layer at a top of the top plate, and wherein the weak aerasare modified to remove the steel layer.
 14. The energy storage system ofclaim 8, wherein the weak areas in the top plate are physically weakerportions of the top plate.
 15. The energy storage system of claim 8,wherein the weak areas are structural depressions in the top plate suchthat the structural depressions are on the interior side of the topplate and the exterior side is planar.
 16. The energy storage system ofclaim 8, wherein the top plate is prepared from a single material and aportion of material is removed from the weak areas.
 17. The energystorage system of claim 8, wherein the top plate is prepared from acomposite material.
 18. The energy storage system of claim 8, whereinthe weak areas are chemically weaker portions of the top plate.
 19. Theenergy storage system of claim 8, further comprising a cold plate inthermal connection with the plurality of battery cells.
 20. The energystorage system of claim 8, wherein the first end of the battery cellsare facing towards the top plate and wherein the second end of thebattery cells are facing away from the top plate and towards a coldplate.